Flame retardant composite articles

ABSTRACT

A flame-retardant composite article has a core of a normallycombustible material (e.g. a foam), the core being surrounded (at least partially) by a combination of (a) a flexible, intumescent, char-forming material and (b) a textile fibrous material. The composite article is of particular use in upholstery components, especially in conditions where there is a fire hazard.

United States Patent Whittaker et al.

[ 1 June 10, 1975 FLAME RETARDANT COMPOSITE ARTICLES Inventors: Kenneth Whittaker; David Ronald Morgan, both of Sutton Coldfield, England Assignee: Dunlop Limited, London, England Filed: June 24, 1974 Appl. No.: 482,584

Foreign Application Priority Data May 29, 1973 United Kingdom 33663/73 US. Cl. 428/262; 428/272; 428/274;

428/921 Int. Cl. D03d 25/00; 1332b 5/18 Field of Search 117/136, 137, 138; 161/89, 161/92, 93, 159, 160, 403, 190

[56] References Cited UNITED STATES PATENTS 3,202,567 8/1965 Muri et a1. 161/403 3,622,432 11/1971 McCluer 161/403 Primary Examiner-William J. Van Balen Attorney, Agent, or Firm-Stevens, Davis, Miller & Mosher [5 7 ABSTRACT The composite article is of particular use in upholstery components, especially in conditions where there is a fire hazard.

11 Claims, N0 Drawings 1 FLAME RETARDANT COMPOSITE ARTICLES This invention relates to flame-retardant composite articles, and in particular to flame-retardant composite articles for cushioning.

According to the present invention, there is provided a flame-retardant composite article comprising a core of one or more combustible materials, at least partly covered by a combination of (a) one or more flexible intumescent char-forming materials, and (b) one or more textile fibrous layers, said combination forming at least one layer or zone.

Any normally-combustible cushioning material may be used for the core of the flame-retardant composite articles of this invention. In particular, foams commonly used in the manufacture of furniture, upholstery and bedding (e.g. polyurethane foam, latex foams and the like) may be used. Other suitable cushioning materials include soft fibrous felts, coiled hair and the like.

The intumescent materials used in the present invention are materials which form a viscous liquid froth when first exposed to a flame, the froth being converted to a rigid carbonaceous char as heating continues. Particularly suitable intumescent materials for the purpose of this invention are the intumescent polyurethane foams produced in accordance with the process of U.S. Pat. No. 3,681,273. One such intumescent foam is commercially available as PYREL from Scott Paper Company. (PYREU is a Registered Trade Mark).

Wool batting is another suitable intumescent material for use in the present invention.

The fibrous textile material may be in the form of a woven, non-woven or knitted fabric. Each layer of textile material may be situated either inside or outside the layer of intumescent char-forming material, so that each layer of textile material is in contact with said intumescent char-forming material. (The expressions inside" and outside are used with reference to the combustible core).

When the layer of textile material is situated outside the intumescent material, it may take the form of a decorative covering material for the composite article. Alternatively, the composite article may be provided with a separate, preferably decorative, covering layer.

In general any textile material may be used. However, it is preferred to use a textile material which on burning leaves a charred skeleton (e.g. cotton and rayon).

In a preferred embodiment of the present invention, the textile material may be made from fibres which have been coated with an intumescent material. In a further embodiment, the textile material may be made from more than one set of fibres, at least one of such sets of fibres being fibres made from an intumescent material.

When a textile material is not included in the composite article, a non-continuous charred surface is formed on heating, which allows the combustible core to burn unless relatively thick layers of the intumescent material are used.

When the textile material is included, it appears to hold the viscous froth in a continuous sheet, until the rigid char has formed, thus allowing the use of relatively thin sheets of intumescent char-forming material.

The flame-retardant composite articles of the present invention may be used as cushioning materials in any application where there is a fire risk, e.g. furniture upholstery, bedding and the like.

The present invention will be further illustrated by way of the following examples.

EXAMPLE 1 The following test samples were prepared:

A. A 5 cm X 5 cm X 10 cm block ofa flexible polyetherurethane foam of 20 kg/m density.

B. As A with a cover a moquette fabric having 23 threads per inch of a 5s cotton-count polyacrylonitrile yarn in the warp and 51 threads per inch of a cotton-count yarn in the weft and weighing about 400 g/m C. As A covered with a 3.7 mm-thick sheet of a flame-retardant intumescent polyesterurethane foam of the type described in U.S. Pat. No. 3,681,273 and being of 40 kg/m density.

D. As C with a cover of the moquette fabric described for B.

E. As D, but with the flame retardant intumescent foam layer replaced by a 4.0 mm-thick layer of a flame retardant foam incorporating 12 percent by weight of tris .dibromopropyl phosphate, having a density of 37- kg/m and having a burnt length of about 60 mm before self-extinguishing according to BS 4735.

Each of the above samples was subjected to a flame from a small propane blow-torch, the propane gas being burnt at 0.4 g/minute. In all cases, ignition of the EXAMPLE 2 Test samples similar to those of Example 1D were prepared, using different thicknesses of the flame retardant intumescent char-forming foam, different methods 0f fixing this foam and the fabric around the polyetherurethane foam block, and different fabrics. These samples were suspended and ignited by a match.

Samples F to N were covered with the moquette fabric of Example 1. Samples 0, P, Q were covered with a damask weave fabric having 84 threads per inch of 24-count span rayon in the warp and 43 threads per inch of 400 denier continuous viscose rayon filament in the weft, and weighing about 150 g/m Samples R, S were covered with a plain-weave fabric having 60 threads per inch of 20-count cotton yarn in both the warp and the weft, and weighing about g/m The results are shown in the Table below:

polyetherurethane block with neoprene-based adhesive, and this composite, foam block covered with -Contmued Thickness of Residual non-burning polyethcr foam layer Method of fixing foam foam as (mm) and fabric layer percentage of original a close-fitting cotton-stitched Cover of the fabric. G 1.7 As "F" 70 H 4.6 As F" 79 l 6.4 As F 82 J 8.9 As F 87 K 3.7 Non-burning foam layer adhered 69 to the fabric with neoprene-based adhesives. and a close-fitting cover made for the polyetherurethane foam block by stitching this foam/fabric laminate. L 5.1 As K 79 M 6.9 As K" 93 N 8.9 As K 87 O 3.6 Non-burning foam cover stitched" 92 with metal staples, but not adhered or stitched to the polyetherurethane foam block: textile cover stitched with metal stapled but not fixed to the underlying foam layer. P 4.3 As O 97 O 4.3 As 99 R 4.1 As 0" 78 S 6.1 As 0" 99 EXAMPLE 3 A cm X 10 cm X 10 cm cube of flexible polyetherurethane foam of kg/m density was covered with a 10 mm thick layer of intumescent char-forming flexible polyesterurethane foam of the tyre used in Example 1, but having a density of 74 kg/m: the composite foam block was covered with the damask fabric of Example 2 O.

A crumpled sheet of newspaper was placed on a wiremesh-topped table, the covered foam cube was placed on top of this, and encircled by two further crumpled sheets of newspaper, the sheets being stapled together so as to ensure close contact between the paper and the sample throughout the test; The weight of newspaper used was about 50 g.

The bottom layers of newspaper were ignited in several places, and the whole assembly allowed to burn until self-extinguishing occurred. The outer surface of the sample was charred, but when cut open it was found that 95 percent of the polyetherurethane foam was intact.

EXAMPLE 4 An intumescent, non-cellular polyurethane was prepared from the following formulation:

a) FOMREZ 50 77.5 parts by weight b) Tolylene di-isocyanate 22.5

c) PU-l604 14.0

d) EDA-260 6.0

e) PHOSCHEK P- 20.0

Notes:

a) FOMREZ 50 is a partially-branched diethylene glycol polyadipate having a hydroxyl number of approximately 50. (*FOMREZ is a Registered Trade Mark). b) An 80:20 mixture of 2,4- and 2.6-tolylene diisocyanate. c) PU-l604 is an isobutyl ester of 4-chloro-3,5-

diamino-benzoic acid.

d) EDA 260 is a substituted ethylene diamine having the formula e) PHOSCHEK P-30 is an ammonium polyphosphate (PHOSCHEK" is a Registered Trade Mark.)

A square-woven cotton fabric I76 g/m was coated on one side with a 0.6 mm-thick layer of the noncellular polyurethane described in the immediately preceding paragraph. The coated fabric was heated at 100C for 20 minutes to complete the polyurethaneforming reaction, before being used to cover a 10 X 10 X 10 cm cube of flexible polyurethane foam.

The covered cube was subjected to the burning test of Example 3 (above). At the end of the test. percent of the foam was found to be intact.

EXAMPLE 5 A composition was prepared from the following formulation:

a) HYPALON 20 42.0 parts by weight Zinc borate 8.0 Antimony (lll) oxide 7.5 b) CERlCLOR 70 7.5

Notes:

a) HYPALON 20 is a chlorosulphonated polyethylene (HYPALON is a Registered Trade Mark).

b) CERICLOR 70 is a chlorinated aliphatic hydrocarbon mixture containing 70% chlorine by weight. (CERICLOR is a Registered Trade Mark).

A square-woven nylon fabric (210 g/m was coated on both sides with the above-described HYPALON formulation. After subjection of the coated fabric to the burning test of Example 3 (above), using a 10 X 10 X 10 cm cube of polyurethane foam as the core, no weight-loss of the foam occurred, the core being only slightly discoloured.

EXAMPLE 6 A 10 X 10 X 10 cm cube of polyurethane foam was covered with the HYPALON foam of Example 5 and the rayon damask fabric of Example 2P, and the composite was subjected to the burning test of Example 3. No weight-loss occurred in the foam core.

EXAMPLE 7 Wool fibres, treated so that 0.5 percent by weight of titanium was present (see J. Textile Inst. (1974,)65, 102) were carded, cross-laid and lightly needled to form a batt, 4 mm thick, weighing 180 g/m The batt was placed between two pieces of a square-woven cotton fabric (l20 g/m and the composite stitched together so that the stitching formed a pattern of l-inch squares.

The batt-fabric composite was used to cover a 10 X 4 X 2 cm block of polyurethane foam. The covered foam block was then suspended 1 inch above 15 g of crumpled newspaper, the newspaper then being ignited and allowed to burn completely.

After burning, percent of the original foam core remained.

When the experiment was repeated with the omission of the cotton fabric, only 50 percent of the foam core remained after burning.

When the experiment was again repeated. omitting the wool batt, the foam core was completely burned away.

EXAMPLE 8 Two sheets of the wool batt of Example 7 were needled on either side ofa sheet of the FY REL foam of Example 3. The batt PYREL composite was used to cover five faces of a l l X l 1 X 5 cm block of polyurethane foam, the sixth face of the foam being covered by an 1 1 X l 1 cm piece of 3-mm hardboard. The composite article so formed was then covered with a sheet of square-woven cotton fabric (120 g/m the fabric and batt PYREL composite being secured to the underside of the hardboard by means of wire staples.

Two burning tests were carried out as follows:

a. the composite was suspended flat" at a height of 4 inches above 30g crumpled newspaper (the hardboard-covered surface being nearest the newspaper), which was then ignited and allowed to burn completely.

b. the composite was then suspended so that the hardboard surface was vertical. one corner being at a height 4 inches above a further 30g crumpled newspaper.

After ignition and burning of the newspaper, 90 percent of the foam core was found to be intact.

In each of tests a) and b) (above) the composite was self-extinguishing after the newspaper had burned away completely.

EXAMPLE 9 The wool batt of Example 7 (above) was needled to both sides of a 5 mm sheet of PYREL foam. The batt PYREL composite was used to cover a 8 X 6 X 3 cm block of natural rubber latex foam, the foam having a density of 65 kg/m. The outer layer was the squarewoven cotton fabric described previously.

The composite was suspended at a height 2 inches above g crumpled newspaper, which was ignited and allowed to burn completely.

After ignition and burning of the newspaper, 75% of the latex foam core was found to be intact.

Although the flame-retardant composites of the prescut invention have been described with particular reference to the use of foam cores, it is to be understood that other, non-combustible, fillings (e.g. metal springs) may be used in conjunction with the core material.

Having now described our invention what we claim is:

l. A flame-retardant composite article having a core made from at least one combustible material. wherein said core is covered, at least in part, by a combination of a. at least one flexible, intumescent, char-forming material; and

b. at least one textile fibrous layer, said combination forming at least one layer or zone.

2. An article as claimed in claim 1, wherein said intumescent char-forming material is a cellular material.

3. An article as claimed in claim 2, wherein said intumescent char-forming material is selected from the class consisting of polyurethane foams and chlorosulphonated polyethylene foams.

4. An article as claimed in claim 1, wherein said intumescent char-forming material is a non-cellular material.

5. An article as claimed in claim 4, wherein said intumescent char-forming material is a non-cellular polyurethane.

6. An article as claimed in claim I, wherein said intumsecent char-forming material is a fibrous material.

7. An article as claimed in claim 6, wherein said intumescent char-forming material is wool batting.

8. An article as claimed in claim 1, wherein said textile fibrous material is selected from the class consisting of nylon, rayon and cotton.

9. An article as claimed in claim 1, wherein said combustible core is made from a material selected from the class consisting of polyurethane foams, latex foams, felt and coiled hair.

10. An article as claimed in claim 1, wherein said textile fibrous material is made from fibres which have been coated with an intumescent material.

1 1. An article as claimed in claim 1, wherein said textile fibrous material is made from more than one set of fibres, at least one of such sets being fibres of an intumescent material. 

1. A FLAME-RETARDANT COMPOSITE ARTICLE HAVING A CORE MADE FROM AT LEAST ONE COMBUSTIBLE MATERIAL, WHEREIN SAID CORE IS COVERED, AT LEAST IN PART, BY A COMBINATION OF A. AT LEAST ONE FLEXIBLE, INTUMESCENT, CHAR-FORMING MATERIAL; AND B. AT LEAST ONE TEXTILE FIBROUS LAYER, SAID COMBINATION FORMING AT LEAST ONE LAYER OR ZONE.
 2. An article as claimed in claim 1, wherein said intumescent char-forming material is a ceLlular material.
 3. An article as claimed in claim 2, wherein said intumescent char-forming material is selected from the class consisting of polyurethane foams and chlorosulphonated polyethylene foams.
 4. An article as claimed in claim 1, wherein said intumescent char-forming material is a non-cellular material.
 5. An article as claimed in claim 4, wherein said intumescent char-forming material is a non-cellular polyurethane.
 6. An article as claimed in claim 1, wherein said intumsecent char-forming material is a fibrous material.
 7. An article as claimed in claim 6, wherein said intumescent char-forming material is wool batting.
 8. An article as claimed in claim 1, wherein said textile fibrous material is selected from the class consisting of nylon, rayon and cotton.
 9. An article as claimed in claim 1, wherein said combustible core is made from a material selected from the class consisting of polyurethane foams, latex foams, felt and coiled hair.
 10. An article as claimed in claim 1, wherein said textile fibrous material is made from fibres which have been coated with an intumescent material.
 11. An article as claimed in claim 1, wherein said textile fibrous material is made from more than one set of fibres, at least one of such sets being fibres of an intumescent material. 